Analysis of Residual Gasoline
To test this out, I performed some small-scale experiments using various gasolines and diesels, as well as paint thinner, charcoal lighter fluid, and mineral spirits – don’t worry, no crimes were committed during this experiment. I used methylene chloride to do a simple solvent extraction of the fire debris and ran the samples by GC-VUV, using VUV Analyze™ to handle the automated data analysis. Here’s what I found.
Figure 1. Comparison of paraffin, isoparaffin, olefin, naphthene, and aromatic (PIONA) content of two gasoline samples extracted from simulated fire debris (top). Chromatographic overlay of the two extracts (middle, bottom). Notice that the samples have many of the same peaks, but they are easily distinguishable by PIONA analysis.
In this example, two of the gasoline samples have many of the same peaks, which could make it more difficult to distinguish them by chromatographic pattern matching alone. Additionally, because the samples mostly share the same compounds, finding individual compounds unique to each sample would also be difficult. However, by taking advantage of VUV’s quantitative power, we’re able to measure the paraffin, isoparaffin, olefin, naphthene, and aromatic (PIONA) content of each sample. Looking at the results, an analyst could easily distinguish these two samples!